At the time of the rebranding, a number of us noted there already was a Windows Phone/Windows 8 music app in the Windows Store called "Groove Smart Music Player." That app was developed by a Montreal-based startup, Zikera.

Update: My original blog post said Microsoft had bought Zikera. But one of Zikera's founders told me via e-mail Microsoft has only bought Groove and not Zikera itself. That's why I changed the blog post headline from my original.

"Microsoft acquired everything from Groove (technology and brand). We can't really comment more details on the deal however," said Zikera's CEO Tri Nguyen.

The post announcing that Groove had been acquired by Microsoft doesn't actually say when Microsoft bought the company. It does note, however that the pre-existing Groove player is no longer available for download. Current users may continue to use the app, but the team won't be updating it further, today's blog post says.